Cetera has posted the contents of a letter he apparently sent to Rock and Roll Hall of Fame producers Alex Coletti and Joel Peresman sharing the bad news. There had been overtures on both sides in advance of Chicago's long-awaited induction, spiking hopes for what might have been the first joint appearance since Cetera split in 1985, but discussions over a set list apparently broke down.

"Unfortunately, this scenario doesn’t work for me," Cetera wrote. "I know we all did our best to make it happen, but I guess it’s just not meant to be. Personally, I’m frustrated and tired of dealing with this, and it’s time to move on. I have a life with two beautiful daughters and a solo career, and its time to get back and give them all the full attention they deserve."

Back in December, former bandmate Robert Lamm initially confirmed that they'd reunite, only to receive a stern rebuttal from Cetera – who said he had "emphatically declined" the opportunity to join them onstage. Then Cetera seemed to relent, even discussing what key Chicago could play "25 or 6 to 4" in, before this latest setback.

Drummer Danny Seraphine, who followed Cetera out the door in 1990, is publicly asking for his former bandmate to reconsider. "It would mean the world to me, to all our wonderful fans – and, in the end, I believe it would to you as well," Seraphine said on Facebook. "Take this rare opportunity to end all this bad blood between us and celebrate the great legacy of music we all created together that has endured the test of time for 49 years. We owe this to our fans and the music."